California
Grass Tribes (Bluegrass, Oat, Brome,
Melic, Wheat, Needlegrass, Reed,
Lovegrass, Bermuda Grass, Summary Key)
By Bruce
Homer-Smith
Summary Key
Tribe |
Infl Branched |
Special Characteristics |
||
Y |
YN |
Short,
membranous |
Infl may be
contracted. Small spikelets.
Leaf collar hairy. |
|
Y |
YN |
Long,
papery |
Infl may be
contracted. Awns from floret back, not
the tip. |
|
Y |
Mostly |
Short. Florets visible. |
Infl may be
contracted. Spikelets widen, then
taper. |
|
YN |
Mostly
not |
Short,
papery. Florets visible. |
Leaf sheath closed. Florets cylindrical, not flattened, papery
edges. |
|
N |
YN |
Short. |
Spikelets
in two ranks and press into stem. |
|
Y |
Mostly |
Long,
membranous |
Bunch
Grass. Awns to 9”. Floret cylindrical, not flat, rigid. |
|
Y |
Mostly
not |
Long,
covers the florets |
Tall,
plume inflorescences except Oatgrass. Silky hairs. |
|
Many
times |
YN |
Short |
Small
spikelets, hairy leaf sheaths, glands on both. |
|
YN |
N |
Short. |
Rows
of small spikelets attach to finger-like branches. |
Infl = Inflorescence
Here are the grass tribes you’re most likely to encounter
in California:
Bluegrass
Tribe (Poeae)
Diagram © Tatiana Sendusky, ‘Agnes Chase’s First Book of Grasses’, 4th edition
Annotations Bruce Homer-Smith
Spikelets are small, with several florets.
They’re membranous or leathery.
If present (e.g. Festuca), awns
are straight and come from the tip of the floret.
Glumes are membranous and shorter than the
whole spikelet, so florets show above them
The inflorescence is branched but may be
contracted or open. Non-woody stems do
not branch before the inflorescence. Leaf collars are not hairy.
Common
CA genera: Briza (Rattlesnake
Grass), Cynosurus (Dogtail Grass), Dactylis
(Orchard Grass), Festuca (Fescue),
Gastridium, Lamarckia (Golden Top), Poa (Blue
Grass), Puccinellia (Alkali Grass), Scribneria.
Exception
– Festuca perennis has a spike-like inflorescence.
Oat
Tribe (Aveneae)
Diagram © Lynn Clark, ‘Agnes Chase’s First Book of Grasses’, 4th edition
Annotations Bruce Homer-Smith
Spikelets have one to many florets that are flattened. Florets sometimes have awns that come from the back, not the tip. Awns can be straight or bent, as in the
diagram.
Long glumes, often papery, usually cover the
rest of the spikelet.
The inflorescence is branched but may be
contracted or open.
California
Genera: Agrostis (Bent Grass), Aira (Hair Grass), Avena (Oats),
Calamagrostis (Reed Grass), Holcus (Velvet Grass), Phalaris (Canary Grass), Phleum (Timothy),
Trisetum (Oat Grass), Polypogon (Beard Grass), Alopecurus,
Ammophila, Anthoxanthum, Arrhenatherum, Beckmannia, Cinna, Hierochloe,
Koeleria, Sphenopholis.
Brome
Tribe (Bromeae)
Diagram © Lynn Clark, ‘Agnes Chase’s First Book of Grasses’, 4th edition
Annotations Bruce Homer-Smith
Spikelets widen from the base and then taper as florets get smaller at the tip.
Glumes are shorter than the lowest floret,
allowing the many florets to show above them.
Florets
are flattened and usually have straight or recurved awns, starting near the tip. They’re herbaceous or leathery, not
membranous.
The inflorescence is branched but may be
contracted or open.
The
closed leaf sheath ends in a characteristic
V-shaped top.
California
Genus: Bromus (Brome).
Melic
Tribe (Meliceae)
Photo by Keir Morse |
Photo © Neal Kramer |
The inflorescence is branched but is so contracted in
many Melicas that it looks spike-like.
Spikelets have short, papery glumes, several florets and no awns.
Florets
are cylindrical, not flattened. They
have papery edges.
Leaf sheaths are closed.
Exception
– Awned Melic (M. aristata) has awns.
The
only California genus in this tribe is Melica.
More on
the Melica
Tribe.
Wheat
Tribe (Triticeae)
Diagram © Lynn Clark, ‘Agnes Chase’s First Book of Grasses’, 4th edition
Spikelets are flattened, and connect directly to
the stem in two ranks. Spikelets press into the stem which is often
indented at the spikelet.
Glumes are shorter than the one-to-many
florets.
Some
leaf blades have ear-like flaps (auricles) where they join the sheath (Hordeum and Elymus)
California
Genera: Aegilops, Agropyron, Elymus (Wild Rye), Hordeum
(Barley), Leymus, Secal (Rye), Triticum
(Wheat)
More on
the Wheat
Tribe.
Needlegrass Tribe (Stipeae)
Purple Needle Grass (Stipa pulchra)
Drawing © John Muir Laws
These are bunch grasses with narrow, branched inflorescences.
Spikelets have a single cylindrical floret, commonly with an awn from 1/8” to 9” long, sometimes bent.
The floret is membranous
to rigid.
Glumes are membranous and long enough to
hide the floret.
The
primary California genus is Stipa (Needle Grass).
Reed Tribe (Arundineae)
Diagram © Lynn Clark, ‘Agnes Chase’s First Book of Grasses’, 4th
edition
Annotations Bruce Homer-Smith
These
are tall, reed-like grasses with tall, plume-like inflorescences. Exception: oat grasses are smaller.
Florets are surrounded by silky hairs.
Glumes cover the florets.
California
Genera: Arundo (Giant Reed), Cortaderia (Pampas Grass),
Danthonia (Oatgrass) and Phragmites (Common Reed).
Lovegrass Tribe (Eragrostideae)
Diagram © Lynn Clark, ‘Agnes Chase’s First Book of Grasses’, 4th edition
Annotations Bruce Homer-Smith
Lovegrass inflorescences are much branched (twice
or thrice divided is common) but the branches may be hard to see because
they’re short.
Spikelets have
3-to-many, hairless, flattened florets
showing over short glumes.
Ligules have hairs
on their margin (ciliate), as do the tops of the leaf
sheaths.
Leaf sheaths and spikelets have characteristic
glands on their surface.
California
Genera: Erigrostis
(Love Grass), Distichlis (Salt
Grass), Eleusine (Goosegrass), Leptochloa
(Sprangletop), Muhlenbergia (Muhly), Sporobolus
(Dropseed), Tridens.
Bermuda Grass Tribe (Cynodonteae)
Diagram © Tatiana Sendusky, ‘Agnes Chase’s First Book of Grasses’, 4th edition
Annotations Bruce Homer-Smith
This
tribe is easy to pick out, with rows of spikelets
attaching on one side of the branch. Spikelets are tiny, each attaching directly
to its branch.
Branches
are whorled at the top of the stem (digitate) or extend from the main stem.
California
Genera: Bouteloua (Gramma), Chloris (Finger Grass), Cynodon (Bermuda Grass), Hilaria (Galleta),
Spartina (Cord Grass).
Corrections/Comments: bruce@PlantID.net Copyright: https://PlantID.net/Contributors.aspx |